The present invention relates, in general, to a diaphragm valve for control of flow of a fluid through a pipe.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
A diaphragm valve typically includes a valve body forming a valve seat in the form of a web for example. A compressor which can be actuated by a valve stem is provided for operating a diaphragm between a closing position in which the diaphragm is pressed against the valve seat to inhibit a flow of fluid through the pipe, and an open position, in which the diaphragm is detached from the valve seat to allow a fluid flow.
Diaphragm valves while finding application in many fields are unsuitable when a flow of sensitive fluids is involved, like in the food and pharmaceutical industries because the fluid-carrying passageways cannot be cleaned thoroughly and completely enough by means of cleaning bodies, also called “scrapers” to meet hygienic standards. In order to meet these stringent requirement, the cleaning body must be able to pass also the valve region, in particular the area of the diaphragm, without being obstructed by projecting parts such as valve seats or the like. In other words, the cross section of the fluid passageways and in the area of the diaphragm valve must be substantially clear. Because of the presence of projecting parts, conventional diaphragm valves do not permit an unhindered passage of such cleaning bodies.
It would therefore be desirable and advantageous to provide an improved diaphragm valve which obviates prior art shortcomings and allows an unhindered passage of cleaning bodies and which is simple in construction while being reliable in operation and cost-efficient.